This fix changes how the intersections loop ignores previously
intersected faces. It now marks them by their index so that subsequent
iterations ignore them.

Before this change, after an intersection was found the start point was
advanced by a small amount to move the past the intersection. The
problem with this was if multiple boundary faces or the end point were
in close proximity to the intersection then the move forward might span
them. This could lead to intersections being missed or counted multiple
times, in some cases indefinitely.

Based on a patch contributed by Mattijs Janssens
Resolves bug report https://bugs.openfoam.org/view.php?id=1147

Merge branch 'wp3-directional-refinement' of develop.openfoam.com:/Customer-VWG/OpenFOAM-plus into wp3-directional-refinement

ENH: fieldMinMax function object - updated for case where there are no cells on a local processor, e.g. CHT

- simply combines (rootPath()/globalCaseName())

- Can now retrieve or set a column/row of a tensor.
  Either compile-time or run-time checks.

  Get
     t.col<1>();   t.col(1);
     t.row<1>();   t.row(1);

  Set
     t.col<1>(vec);   t.col(1,vec);
     t.row<1>(vec);   t.row(1,vec);

  The templated versions are compile-time checked

     t.col<3>();
     t.col<3>(vec);

  The parameter versions are run-time checked

     t.col(3);
     t.col(3,vec);

ENH: provide named access to tensor/tensor inner product as inner()

Helper function to calculate the current face area vs the area returned
from the current point locations.  Useful for ACMI-type baffles where we
scale the face areas without moving points.

- nBoundaryFaces() is often used and is identical to
  (nFaces() - nInternalFaces()).

- forward the mesh nInternalFaces() and nBoundaryFaces() to
  polyBoundaryMesh as nFaces() and start() respectively,
  for use when operating on a polyBoundaryMesh.

STYLE:

- use identity() function with starting offset when creating boundary maps.

     labelList map
     (
         identity(mesh.nBoundaryFaces(), mesh.nInternalFaces())
     );

  vs.

     labelList map(mesh.nBoundaryFaces());
     forAll(map, i)
     {
         map[i] = mesh.nInternalFaces() + i;
     }

chtMultiRegionSimpleFoam

Previously had 3 possibilities for handling exposed internal faces

  1. use default "oldInternalFaces"
  2. specify -patch, to use the specified (existing) patch
  3. specify -patches, to use the geometrically closest patches

Now relaxed the restriction on -patch to allow specification of a new
(not yet existing) patch name. This improves flexibility, but won't
catch typing mistakes.

Harmonize behaviour of -patches and -patch. When -patches is used to
specify a single, non-regex patch name, it now behaves identically to
-patch. Since the getList handling for options already allows special
treatment for single parameter lists, the following will work
identically:

      subsetMesh -patch  patch0
      subsetMesh -patches patch0
      subsetMesh -patches '( patch0 )'

In the future it might be reasonable to fully combine the behaviour of
'-patch' and '-patches' and treat them as aliases for each other.

ENH: support subsetMesh on a cellZone.

- when the '-zone' option is specified, the command argument is treated
  as the name (or names) of cellZones to be selected instead of as the
  name of the cellSet.

  The command argument can be a single word, regex, or list of
  word/regex.
  Eg,

      subsetMesh -zone -patch mypatch  mixer
      subsetMesh -zone -patch mypatch  '(mixer "moving.*" )'

STYLE: simplify set handling and other code cleanup in subsetMesh

- handling of cloud coordinates/positions between mapFields, mapFieldsPar

- safeguard against any change in the default in cylindricalCS

    Using: OpenFOAM-plus (see www.OpenFOAM.com)
    Build: plus-7ab57cc5 (OPENFOAM=1807)
    Arch:  LSB;label=32;scalar=64

- This can be useful for development versions, or when the version
  at build time uses some other naming scheme (#1010)

- superseded by the vtkCloud function object, which provides
  significantly more functionality and more versatile output
  (using the vtp format).

- an alternative to distanceSurface (with distance zero) that uses
  a cell cutting approach instead of an iso-surface.

- 'signed' input parameter only mandatory for distance > 0.
  A distance <= 0 is always signed and the input parameter is ignored.

- Use normal distance when distance == 0. This has no effect when
  the surface has no open edges, but improves on rounding issues
  around the zero crossing when the surface has open edges.

  This may still need future revisiting.

- avoid duplicate code by relocating cellZone selection and bounding box
  sub-selection into cuttingPlane and cuttingSurfaceBaseSelection.
  Allows reuse by inherited classes (sampledPlane, surfMeshSamplePlane).